test: remove common.PORT from test-net-timeout

Switch test-net-timeout from common.PORT to a port assigned by the
operating system.

PR-URL: https://github.com/nodejs/node/pull/31749


Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>